This invention relates to a spool having means at the ends thereof for automatically gripping a filament to be wound thereon. Such a spool is particularly useful in an apparatus for continuously winding filament, thread or the like on a plurality of spools.
There is presently a need for an apparatus for continuously winding glass optical waveguide filament on a plurality of spools during the drawing thereof. Such apparatus must have means for automatically changing spools, i.e., removing from the winding station a spool that is full, severing the filament from the full spool, and attaching the filament to an empty spool that has been moved into the winding station.
The spool of the present invention is particularly applicable to the winding of relatively fragile filaments such as glass optical waveguides. The characteristics of such optical waveguides and methods of making the same are disclosed in the publication "Doped-Deposited-Silica Fibres For Communications" by R. D. Maurer, Proc. IEE, Vol. 123, No. 6, June, 1976, pp. 581-585. Such fibers are manufactured by initially forming a glass preform from which filaments are drawn. Drawing speeds up to 2 meters per second have been achieved, and speeds up to 5 meters per second are anticipated in the near future. Up to 15 km of filament have been produced from a single glass blank, and the drawn filament is wound on spools containing as little as 25 meters per spool. After the desired length of filament is wound on a spool, it is very difficult if not impossible for an operator to change spools by hand when filament drawing speeds exceed one meter per second. An automatic apparatus for performing this function must be capable of removing a full spool from the winding station, attaching the filament to an empty spool and continuing to wind the filament without breaking it or causing damage thereto, without interrupting the drawing of the filament and without generating an undue amount of waste filament. The filament should not be sharply bent, and the ends thereof should protrude from the spools to facilitate the connection of testing equipment thereto. Presently available spools are incapable of meeting these requirements.